Yeah, only theists think in absolute truths. For science, everything is open to question, even if it seems decided beyond all doubt - who knows what new discovery will enhance our understanding?
That's why evolution is a theory ... as is gravity, because we know we don't know everything about it yet. But I know I'm not going to float off into space anytime soon.
The trouble is the conflation with the layman's use of the world 'theory' which usually equates to a guess. The irony being that religious belief is almost completely guesswork or wishful thinking and fits the lay term "theory" better.